runtime/objc-sel.m

   1 /*
   2  * Copyright (c) 1999-2007 Apple Inc.  All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  *      Utilities for registering and looking up selectors.  The sole
  26  *      purpose of the selector tables is a registry whereby there is
  27  *      exactly one address (selector) associated with a given string
  28  *      (method name).
  29  */
  30
  31 #include <objc/objc.h>
  32 #import "objc-private.h"
  33 #import "objc-auto.h"
  34 #import "objc-rtp.h"
  35 #import "objc-sel-set.h"
  36
  37 // _objc_builtin_selectors[]
  38 #include "objc-sel-table.h"
  39
  40 // from phash.c
  41 extern uint32_t phash(const char *key, int len);
  42
  43 #define NUM_NONBUILTIN_SELS 3500
  44 // objc_sel_set grows at 3571, 5778, 9349.
  45 // Most apps use 2000..7000 extra sels. Most apps will grow zero to two times.
  46
  47 static const char *_objc_empty_selector = "";
  48 static OBJC_DECLARE_LOCK(_objc_selector_lock);
  49 static struct __objc_sel_set *_objc_selectors = NULL;
  50
  51
  52 static inline int ignore_selector(const char *sel)
  53 {
  54     // force retain/release/autorelease to be a constant value when GC is on
  55     // note that the selectors for "Protocol" are registered before we can
  56     // see the executable image header that sets _WantsGC, so we can't cache
  57     // this result (sigh).
  58     return (UseGC &&
  59             (  (sel[0] == 'r' && sel[1] == 'e' &&
  60                 (_objc_strcmp(&sel[2], "lease") == 0 ||
  61                  _objc_strcmp(&sel[2], "tain") == 0 ||
  62                  _objc_strcmp(&sel[2], "tainCount") == 0 ))
  63                ||
  64                (_objc_strcmp(sel, "dealloc") == 0)
  65                ||
  66                (sel[0] == 'a' && sel[1] == 'u' &&
  67                 _objc_strcmp(&sel[2], "torelease") == 0)));
  68 }
  69
  70
  71 static SEL _objc_search_builtins(const char *key) {
  72     const char *sel;
  73     uint32_t hash;
  74
  75 #if defined(DUMP_SELECTORS)
  76     if (NULL != key) printf("\t\"%s\",\n", key);
  77 #endif
  78
  79     /* The builtin table contains only sels starting with '[.A-z]', including '_' */
  80     if (!key) return (SEL)0;
  81     if ((intptr_t)key == kIgnore) return (SEL)kIgnore;
  82     if ('\0' == *key) return (SEL)_objc_empty_selector;
  83     if ((*key < 'A' || 'z' < *key)  &&  *key != '.') return (SEL)0;
  84     if (ignore_selector(key)) return (SEL)kIgnore;
  85
  86     hash = phash(key, (int)__builtin_strlen(key));
  87     sel = _objc_builtin_selectors[hash];
  88     if (sel  &&  0 == __builtin_strcmp(key, sel)) return (SEL)sel;
  89     else return (SEL)0;
  90 }
  91
  92
  93 const char *sel_getName(SEL sel) {
  94     if ((intptr_t)sel == kIgnore) return "<ignored selector>";
  95     return sel ? (const char *)sel : "<null selector>";
  96 }
  97
  98
  99 BOOL sel_isMapped(SEL name) {
 100     SEL result;
 101
 102     if (NULL == name) return NO;
 103     result = _objc_search_builtins((const char *)name);
 104     if ((SEL)0 != result) return YES;
 105     OBJC_LOCK(&_objc_selector_lock);
 106     if (_objc_selectors) {
 107         result = __objc_sel_set_get(_objc_selectors, name);
 108     }
 109     OBJC_UNLOCK(&_objc_selector_lock);
 110     return ((SEL)0 != (SEL)result) ? YES : NO;
 111 }
 112
 113 static SEL __sel_registerName(const char *name, int lock, int copy) {
 114     SEL result = 0;
 115
 116     if (NULL == name) return (SEL)0;
 117     result = _objc_search_builtins(name);
 118     if (result != NULL) return result;
 119
 120     if (lock) OBJC_LOCK(&_objc_selector_lock);
 121
 122     if (_objc_selectors) {
 123         result = __objc_sel_set_get(_objc_selectors, (SEL)name);
 124     }
 125     if (result == NULL) {
 126         if (!_objc_selectors) {
 127             _objc_selectors = __objc_sel_set_create(NUM_NONBUILTIN_SELS);
 128         }
 129         result = (SEL)(copy ? _strdup_internal(name) : name);
 130         __objc_sel_set_add(_objc_selectors, result);
 131 #if defined(DUMP_UNKNOWN_SELECTORS)
 132         printf("\t\"%s\",\n", name);
 133 #endif
 134     }
 135
 136     if (lock) OBJC_UNLOCK(&_objc_selector_lock);
 137     return result;
 138 }
 139
 140
 141 SEL sel_registerName(const char *name) {
 142     return __sel_registerName(name, 1, 1);     // YES lock, YES copy
 143 }
 144
 145 __private_extern__ SEL sel_registerNameNoLock(const char *name, BOOL copy) {
 146     return __sel_registerName(name, 0, copy);  // NO lock, maybe copy
 147 }
 148
 149 __private_extern__ void sel_lock(void)
 150 {
 151     OBJC_LOCK(&_objc_selector_lock);
 152 }
 153
 154 __private_extern__ void sel_unlock(void)
 155 {
 156     OBJC_UNLOCK(&_objc_selector_lock);
 157 }
 158
 159
 160 // 2001/1/24
 161 // the majority of uses of this function (which used to return NULL if not found)
 162 // did not check for NULL, so, in fact, never return NULL
 163 //
 164 SEL sel_getUid(const char *name) {
 165     return __sel_registerName(name, 2, 1);  // YES lock, YES copy
 166 }
 167
 168
 169 BOOL sel_isEqual(SEL lhs, SEL rhs)
 170 {
 171     return (lhs == rhs) ? YES : NO;
 172 }